This invention relates to a pocket cloth folding device of a pocket setter.
As a method for forming a fold along the peripheral edge of a pocket cloth, Japan Published Unexamined Utility Model Application No. S63-91275 is known. FIG. 2 depicts a pocket cloth folding device of this related-art method. On a table 4 a vertically movable base 10 is provided. A support plate 14 is slidably supported by the base 10 via a cylinder 11, and a support shaft 16 is laid between two projections of the base 10. A press-plate holder 18 and support blocks 30 are movably supported on the support shaft 16. A press plate 19 is detachably connected to the lower ends of the press-plate holder 18, and a piston 22 of an air cylinder 21 is connected to the upper end of the press-plate holder 18. The end of the air cylinder 21 is rotatably provided on the upper surface of the base 10. When the piston 22 of the air cylinder 21 is actuated to extend, the press plate 19 is moved to a pressing position for pressing a pocket cloth placed on the support plate 14. Then, a bending edge 191 formed on the periphery of the press plate 19 bends down the peripheral edge of the pocket cloth. On the contrary, when the piston 22 of the air cylinder 21 is actuated to withdraw, the press plate 19 is shifted to a detached position away from the support plate 14.
A folding-pieces support member 24 having a central space 100 is detachably attached to the lower ends of the support blocks 30. The inside peripheral edge of the folding-pieces support member 24 is in parallel with the outside peripheral edge of the support plate 14. Pistons 29 of air cylinders 28 are rotatably connected to the upper ends of the two support blocks 30 respectively, and the air cylinders 28 are also rotatably connected to both side projections of the base 10. When the pistons 29 of the air cylinders 28 extend, the folding-pieces support member 24 is set at an operational position surrounding the support plate 14. When the pistons 29 withdraw, the folding-pieces support member 24 is shifted to be at a preparatory position above the support plate 14.
On the folding-pieces support member 24, four air cylinders 25 having pistons 26 are provided, to which folding pieces 27 are fixed, respectively. The folding pieces 27 are also shifted between two positions, namely, a projecting position and a withdrawn position when the folding pieces support member 24 is at the operational position. At the projecting position, the folding pieces 27 are set under the support plate 14 by the air cylinder 25 such that the bent peripheral edge of the pocket cloth is folded to the underside of the support plate 14. After the folding operation, the folding pieces 27 are shifted back to the withdrawn position.
In order to sew a pocket cloth on a front cloth with the above-mentioned pocket cloth folding device, an operator places the pocket cloth on the support plate 14 in the state that the base 10 is at an upper position and the support plate 14 is at the projecting position. Then, the press plate 19 is rotated to the pressing position, and the folding-pieces support member 24 is also rotated from the preparatory position to the operational position. Further, the folding pieces 27 are shifted from the withdrawn position to the projecting position so as to fold the peripheral edge of the pocket cloth to the underside of the support plate 14.
Subsequently, the base 10 is moved to a lower position, and the support plate 14, the press plate 19 and the folding-pieces support member 24 are all together lowered onto the front cloth placed on the table 4. Then, the folding pieces 27 are shifted back to the withdrawn position, the folding-pieces support member 24 is rotated to the preparatory position, and the press plate 19 is also rotated to the detached position.
After these operations are finished, a clamp plate 9 is actuated to be positioned above the pocket cloth and presses the pocket cloth onto the body cloth. Then the support plate 14 is slid back by the air cylinder 11 and the base 10 is raised to the upper position The clamp plate 9 pressing the pocket cloth and the front cloth is positioned under the sewing machine head 2. Thus the pocket cloth is sewn on the front cloth.
However, the prior-art pocket cloth folding device has the following problems:
Since the folding-pieces support member 24 is connected to the support blocks 30 only at two ends as a cantilever plate, the free end on which the folding pieces 27 are provided tends to vibrate when the folding-pieces support member 24 is rotated from the preparatory position to the operational position. Under such a condition, the folding pieces 27 may crush against the support plate 14 or the like, thus being damaged.
The speed of the movement of the air cylinders 28 should be accelerated in order to shorten the cycle time from the beginning of the folding operation of the pocket cloth to the end of the sewing operation of the pocket cloth on the front cloth. Consequently, a larger amount of more highly pressured air should be supplied to the air cylinders 28.
To solve these problems in the prior-art pocket cloth folding device, the amount of air flowing into and out of the air cylinders 28 is set such that the vibration of the folding-pieces support member 24 is not excessive. A flow control valve provided in the vicinity of the base 10 controls the amount of the air.
Yet, at sewing factories, a variety of folding-pieces support members 24 are utilized according to pocket cloths of various sizes and shapes. Each time a different type of the pocket cloth is sewn, the flow control valves have to be regulated to fit the weight of the folding-pieces support member 24 corresponding to the pocket cloth to be sewn.